Realization of the T Lineage Program Involves GATA-3 Induction of Bcl11b and Repression of Cdkn2b Expression.

The zinc-finger transcription factor GATA-3 plays a crucial role during early T cell development and also dictates later T cell differentiation outcomes. However, its role and collaboration with the Notch signaling pathway in the induction of T lineage specification and commitment have not been fully elucidated. We show that GATA-3 deficiency in mouse hematopoietic progenitors results in an early block in T cell development despite the presence of Notch signals, with a failure to upregulate Bcl11b expression, leading to a diversion along a myeloid, but not a B cell, lineage fate.

Microdroplet-based one-step RT-PCR for ultrahigh throughput single-cell multiplex gene expression analysis and rare cell detection.

Gene expression analysis of individual cells enables characterization of heterogeneous and rare cell populations, yet widespread implementation of existing single-cell gene analysis techniques has been hindered due to limitations in scale, ease, and cost. Here, we present a novel microdroplet-based, one-step reverse-transcriptase polymerase chain reaction (RT-PCR) platform and demonstrate the detection of three targets simultaneously in over 100,000 single cells in a single experiment with a rapid read-out. Our customized reagent cocktail incorporates the bacteriophage T7 gene 2.

Grb2 regulates the proliferation of hematopoietic stem and progenitors cells.

Although Hematopoietic Stem and Progenitor Cell (HSPC) proliferation, survival and expansion have been shown to be supported by the cooperative action of different cytokines, little is known about the intracellular signaling pathways that are activated by cytokines upon binding to their receptors. Our study showed that Growth factor receptor-bound protein 2 (Grb2) mRNAs are preferentially expressed in HSC compared to progenitors and differentiated cells of the myeloid and erythroid lineages. Conditional deletion of Grb2 induced a rapid decline of erythroid and myeloid progenitors and a progressive decline of HSC numbers in steady state conditions.

CDK6 levels regulate quiescence exit in human hematopoietic stem cells.

Regulated blood production is achieved through the hierarchical organization of dormant hematopoietic stem cell (HSC) subsets that differ in self-renewal potential and division frequency, with long-term (LT)-HSCs dividing the least. The molecular mechanisms underlying this variability in HSC division kinetics are unknown. We report here that quiescence exit kinetics are differentially regulated within human HSC subsets through the expression level of CDK6.

Cord blood expansion. Pyrimidoindole derivatives are agonists of human hematopoietic stem cell self-renewal.

The small number of hematopoietic stem and progenitor cells in cord blood units limits their widespread use in human transplant protocols. We identified a family of chemically related small molecules that stimulates the expansion ex vivo of human cord blood cells capable of reconstituting human hematopoiesis for at least 6 months in immunocompromised mice. The potent activity of these newly identified compounds, UM171 being the prototype, is independent of suppression of the aryl hydrocarbon receptor, which targets cells with more-limited regenerative potential.